Wigan manager Roberto Martinez has accused the Canaries of targeting the Glaswegian in his side's 2-1 defeat that saw the youngster limp off after a challenge from Bradley Johnson.
While the Spaniard could not reveal the full extent of the injury, it is expected that the player, who has started Ireland's six games since Euro 2012, will miss the busy Christmas and New Year schedule.
It could also damage the 22-year-old's prospects of a move away from the DW Stadium, having been linked with Arsenal after some fine form in recent weeks.
"James has been in good form, and they took him out of the game, which is very disappointing," Martinez said.
"It was an infuriating moment and something you don't want to see. The referee saw it, showed a yellow card and I don't think he can do any more than that as a referee.
"Clearly he was targeted. They got away with it. You don't want to see players injured in such a ruthless manner. It was clearly a cynical challenge without the ball to be played for."
McCarthy will undergo an X-ray, but his manager is not hopeful of a swift return and must plan without him for the coming weeks.
"It is his ankle ligaments, we will X-ray it and get the results from the scans very shortly. But I doubt if he will be available for the next 10 days."
The winger played a pivotal role in yet another win for the Canaries on Saturday in front of Ireland assistant Marco Tardelli and former international Hughton backed Pilkington to take the decision.
Pilkington has said that he would be "more than happy" to play for Ireland "if selected" and Giovanni Trapattoni is hoping the paperwork to process his passport is complete to select him for the squad for Ireland's friendly against Poland in February.
"Where we are at the moment is, there has been no call-up for Anthony into any official squad. Until that happens, we're in exactly the same position we have been," said Hughton.
"Any way that it happens, I'm always delighted for any player to be involved at international level.
"It enhances their career and it can provide some real high moments in their career. Yes (I chose Ireland), and for me it was a wonderful decision that I never, ever regretted.
"Anthony is a very mature young man and any big decisions he has to make, he's very capable of making. If it happens, I'll be delighted for him but that's always going to be down to him."